1. Field of the Invention
The present invention generally concerns (i) immersible, underwater and on-water, prime movers that forcibly expel water in jets, (ii) diverse underwater and on-water items including pool cleaners, boats, surf-and-rescue boards, aquatic maneuvering units and scuba apparatus propelled by such prime movers, and also (iii) land-based fountains and water cannons using the water so expelled. The present invention particularly concerns an immersible prime mover powered by compressed air to, upon a triggering event, forcibly expel a slug of water, producing thereby an impulse force that may suitably be used for, among other things, propulsion.
2. Description of the Prior Art
U.S. Pat. No. 4,211,300 to Miller for an AIR GUN WITH RECIPROCATING SHUTTLE having some of the elements of the air-actuated prime mover device of the present invention. Miller shows an improved air gun consists of an elongated cylindrical housing for containing a volume of compressed air that is closed at each end by end plates. A radially-positioned exhaust port is bored into the wall of the housing. A hollow, cylindrical shuttle, is mounted concentrically inside the housing for linear back-and-forth sliding motion in alternate strokes. The ends of the shuttle are closed by end faces. The present invention will also be seen to have a typically cylindrical housing, a reciprocating sliding member that is in part hollow and, in some variants, one or more radially-positioned ports. However, the detail structure, and in gross operation, of the present invention will be seen to be different from the air gun of Miller, who does not put his exhaust air to any particular use.
In Miller's air gun a radially positioned sealing pad has an orifice that may be aligned with the exhaust port which is supported by the shuttle. When the shuttle is at either end of a stroke, the sealing pad blocks the exhaust port. The space between each shuttle end face and the respective housing end plates form shuttle-actuation control chambers. A small air leak in each control chamber maintains the residual air pressure therein at ambient when the guns is inactive. To fire the gun, a small quantity of air is diverted by a valve from inside the housing to one of the control chambers. The inrush of compressed air to the control chamber greatly exceeds the leakage rate of the air leak and accelerates the shuttle towards the opposite end of the housing. During passage from one end of the housing to the other, the orifice in the sealing pad momentarily opens the exhaust port to emit a jet of compressed air. Upon completion of the stroke, the diversion valve is disabled and the residual air pressure in the control chamber returns to ambient.
Also relevant to the prime mover aspect of Applicant's invention is U.S. Pat. No. 4,285,415 to Paitson for an ACOUSTIC IMPULSE GENERATOR. The Paitson invention is directed to producing a powerful acoustic signal, or shock wave. Paitson describes an apparatus for controlling a release of pressurized fluid in order to generate such an acoustic or shock wave impulse for use in underwater reflection seismic surveys. Compressed air is supplied to the acoustic impulse generator and is used both to provide the compressed air acoustic impulse and to retain two piston members in sealing engagement with each other to maintain the compressed air within the apparatus. The two internal pistons are hollow, open-ended cylindrical members, and are adapted to slide axially within a cylindrical chamber and exhaust one another to preclude escape of compressed air. To fire the acoustic impulse generator, compressed air pressure holding the first piston member in position over a series of exhaust ports is suddenly reduced, causing that piston to shift within its chamber, exposing the ports to atmosphere and thereby emitting an acoustic impulse of compressed air. Immediately thereafter, residual air pressure within the device causes the second piston to shift in the same direction following the first piston to again close the exhaust ports and preclude further escape of compressed gas, thus defining an acoustic impulse of finite duration.
Also relevant is United States Patent no. 5,765,374 to Hansen for a GAS DRIVEN MECHANICAL OSCILLATOR AND METHOD showing a sophisticated delivery of compressed gases to a piston oscillating bi-directionally, as will be the case in the present invention. The apparatus and method of Hansen concerns a gas driven oscillator comprising an engine having a cylinder and a pair of expansion chambers on either side of a floating piston adapted to reciprocate within the cylinder. The piston is mounted on a piston rod extending through the cylinder and into a compressor. Compressed air is delivered from a tank to the engine via a pair of valves mounted on an adjustment screw and slidably disposed on the piston rod. The spacing between the valves can be adjusted in order to vary the amplitude of the piston within the cylinder. The piston rod includes spaced slots which alternate align with passages inside the respective valves to deliver a pulse of compressed air to the respective chambers of the cylinder. Mercury is added to or discharged from a tank which is rigidly secured to a piston rod to vary the inertia of the oscillation.
The present invention will also be seen to concern applications of a new prime mover device, notably including as the propulsive unit of a pool cleaner.
In this regard, United States Patent no. 4,169,484 to Bonigut, et. al. for an AUTOMATIC POOL CLEANER APPARATUS concerns an automatic pool cleaner apparatus including an elongated flexible conduit adapted to be connected at one end to a source of water under pressure and adapted to be connected at its other end to the rear of a body portion, said body portion having a plurality of water jet openings further defined on the rear thereof and positioned in a symmetrical relationship about the center line axis of said body portion, such that water discharged therefrom is directed to the rear substantially axially along the direction of said conduit, and further including means for maintaining said body portion in a submerged state, and means for causing said body to be oriented during its movements a substantial portion of the time in positions adjacent to the wall and bottom surfaces of said pool.
Similarly, U.S. Pat. No. 5,293,659 to Rief, et. al. for an AUTOMATIC SWIMMING POOL CLEANER concerns a suction head for a swimming pool cleaner comprising a housing which is open at its lower side and has inclined bristles attached to its lower edge for supporting on a surface to be cleaned. The housing has a rotary sleeve mounted to its top for connection of a suction hose in turn to be connected to a water suction pump. Said sleeve opens in a chamber within the housing in which a vibratory element is pivotally mounted, said element having a crescent or air-foil shape. By a flow of water sucked through said chamber, the vibratory element is automatically brought into a vibrating movement which imparts pulsations on the suction head. Thereby, the inclined bristles are bent and straightened repetitively resulting in a forward thrust moving the suction head over the surface to be cleaned. At least one foot is disposed in the housing which is cyclically displaced vertically by a driving mechanism driven by the movement of the vibratory element and returned by return springs. Said foot cyclically lifts off the suction head at one side, resulting in a rotational movement of the suction head about a vertical axis so as to change the direction of forward movement of the suction head.
Finally, U.S. Pat. No. 5,655,246 to Chang for a PULSATING SUBMERSIBLE POOL CLEANER concerns a pulsating submergible pool cleaner which has a hollow body connected to a pool pump through a flexible hose. An integrated reed valve and relief valve receive the full flow of water from the pump, with the reed valve closing, forcing the relief valve open generating hydraulic cyclic pulsations. An inlet mounting foot is attached to the hollow body and a flexible circular debris removing disc is removably connected to the foot. The foot and disc engage the submerged surface by the suction of the pool pump, and the cleaner is propelled around the pool surfaces by the cyclic pulsation generated by the integrated valves. Debris is removed and ingested into the cleaner by the scrubbing action of the disc, combined with high velocity water flow entering the body under the disc through small passageways. A leaf catching net may be added as an accessory for collecting large debris, such as leaves of plants. The pool cleaner patents in general show that, although air is useful for dislodging and floating debris during pool cleaning, compressed air is an uncommon source of energy for a pool cleaner.